Orthographic projection for 3D plots

[archmoj]

Fixes#2611.
A new attribute ortho is defined on the camera object and passed to various modules.
The scene initialisation is now uses the camera init variables and createCamera is centralised in a separate module (i.e. 3d-view) as it was used by plotly.js as well as 3d-view-controls & gl-plot3d modules.
This is a work in progress and some functions such as zooming and restyle require improvements.
Hint: to quickly test the functionality of this feature with existing 3-D mocks, one may change the dflt of ortho to be equal to true.
@etpinard

[etpinard]

@archmoj how close is this one to being reviewable?

[archmoj]

@archmoj how close is this one to being reviewable?

@etpinard Please let me resolve the conflicts & clean up the commits in a new PR possibly tomorrow.

[etpinard]

& clean up the commits in a new PR possibly tomorrow.

Wanna try to merge master and resolve the conflict instead? Keeping just one PR in our github history. Thanks!

[archmoj]

Now in #3550
Closed.